Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant >= 2n.

Terms

a(0) =1a(1) =0a(2) =5a(3) =26a(4) =83a(5) =203a(6) =456a(7) =853a(8) =1497a(9) =2477a(10) =3860a(11) =5690a(12) =8305a(13) =11470a(14) =15684a(15) =20947a(16) =27328a(17) =35057a(18) =44569a(19) =55569a(20) =68849a(21) =84153a(22) =101912a(23) =122125a(24) =146014a(25) =172246a(26) =202378a(27) =236593a(28) =274399a(29) =316494